Typically, stuffing apparatus is commonly used in the food industry, for example, to automatically stuff food product, e.g., meat emulsion, into a casing length deshirred from a shirred casing supply mounted over a stuffing horn. After the product is stuffed, the casing is constricted and gathered around the end of the stuffed product by closing a pair of gathering plates. The stuffed product is then closed by applying a clip around the gathered end of the casing.
An important recent development in the food packing industry has been the use with food stuffing apparatus of a controllably premoisturized, shirred casing. This particular casing has several significant advantages. First of all, there is no need to soak the casing at the processing plant immediately prior to the stuffing operation. This, of course, saves considerable time, equipment and expense in the production of stuffed products. Furthmore, since the moisture content of the casing is maintained at a controlled level, the casing tends to behave in a predictable fashion on the stuffing apparatus. Finally, since soaking is no longer a requirement, the casing can be shirred to higher pack ratios so that a greater length of casing can be shirred onto a stick of predetermined length. It will be readily apparent that this feature significantly reduces the apparatus downtime due to stick loading.
Casing which is controllably premoisturized to a commercially acceptable level, e.g., from about 15.5% to about 35%, and preferably to about 20%, of total casing weight, is much less pliable than a fully soaked casing. Unfortunately, this has given rise to certain problems in adapting existing stuffing equipment to handle the premoisturized casing. For instance, it has been found that stuffing pressures encountered with premoisturized casing may be significantly higher than those encountered when a fully soaked casing is employed to stuff the casing to the same diameter.
U.S. Pat. No. 4,007,761 to Beckman describes a solution to this problem wherein a sizing disc or ring mounted inside the casing, stretches the casing circumferentially as the casing deshirrs from the casing supply. The sizing disc or ring stretches the casing toward or even beyond its recommended stuffed circumference, which thereby causes the casing to take a temporary set. With the casing stretched to about its recommended stuffed circumference, the emulsion entering the casing need only fill the casing without much, if any, additional stretching, resulting in a substantial reduction in stuffing pressure.
Unfortunately, the placement of a sizing disc or ring inside the casing to stretch the casing creates an additional problem in that the sizing disc or ring establishes a holdback force which, if not relieved, can prevent completion of the gathering and clipping operation without damage to the casing. This problem has been solved in the past by the provision of a tension sleeve. The tension sleeve is mounted over the stuffing horn and carries the sizing disc or ring at its outer end. The tension sleeve is connected at its other end to a reciprocating mechanism which cycles the tension sleeve first aft, then fore, to create a controlled length of slack casing which, in effect, substantially reduces the holdback force developed in the casing supply during gathering. The slack casing so provided is thus available to be drawn by the gathering plates around the end of the stuffed product.
Although the provision of a tension sleeve carrying a sizing disc or ring and reciprocating fore and aft on the stuffing horn has solved the problem of a casing holdback, the solution nevertheless has been a compromise since additional space must be taken from the shirred casing length on the stuffing horn to allow for the reciprocating motion of the tension sleeve. In other words, due to its reciprocating movement, the tension sleeve is shortened and this necessarily results in the loss of available shirred casing, approaching about 25% or at least enough in most cases to considerably dilute the pack ratio advantage offered by the highly compressed controllably premoisturized casing.
U.S Pat. No. 3,748,690 to Niedecker discloses a stuffing apparatus for stuffing sausage casings and the like wherein the stuffing horn is provided with a snubbing ring adjacent to its discharge end. The snubbing ring is arranged to reduce the casing holdback immediately after completion of the filling operation in order to accommodate flowable product that is displaced during the constriction and gathering operation.
Copending application Ser. No. 273,278, now U.S. Pat. No. 4,438,545, of Kupcikevicius et al, filed on June 12, 1981 and assigned to the common assignee hereof, discloses an improved stuffing method and apparatus which is primarily adapted to the utilization of controllably premoisturized casing. In this development, a tension sleeve carrying a sizing disc or ring is provided along with a snubbing ring mounted adjacent to the discharge end of the stuffing horn. The snubbing ring serves to infold the stretched casing as it passes from around the sizing disc or ring and also provides an emulsion seal as the infolded casing passes between the snubbing ring and stuffing horn. Again, the tension sleeve is adapted to reciprocate in order to provide slack in the casing while the snubbing ring is maintained in fixed or stationary position.